Forging machine

ABSTRACT

A forging machine ( 1 ) comprises at least two forging punches ( 3 ) acting against each other and longitudinally guided in a forging box ( 1 ), which forging punches each have separate mechanical lifting drives and preferably vertical position adjusting means. To achieve a rugged lifting drive with high machine rigidities and a simplified construction, the lifting drives are comprised of a wobble plate drive ( 5 ) including a wobble plate ( 6 ) rotatably and drivably, but immovably mounted in the forging box ( 1 ) about a wobble axis (T) offset in parallel to the respective forging punch axis (S), and a pressure plate ( 9 ) associated to the wobble plate ( 6 ) and supported in the manner of a ball-and-socket joint on the end face of the associated forging punch ( 3 ) facing the wobble plate, where preferably the forging punches ( 3 ) can be pressurized via pressure springs ( 11 ) in the sense of a frictional connectoin of wobble plates ( 6 ) and pressure plates ( 9 ).

1. FIELD OF THE INVENTION

This invention relates to a forging machine comprising at least twoforging punches acting against each other and longitudinally guided in aforging box, which each have separate mechanical lifting drives andpreferably vertical position adjusting means.

2. DESCRIPTION OF THE PRIOR ART

In known forging machines, eccentric drives are mostly used asmechanical lifting drives, where the rotary movement of the eccentricsis converted into lifting movements of the forging punches due to acooperation of sliding blocks rotatably mounted on the eccentrics andconnecting rod heads of the forging punches accommodating the slidingblocks. The forging forces which occur during forging therefore apply abending load onto the eccentric shafts via the forging punches, so thatthese eccenctric shafts must be dimensioned and supported accordingly,which involves an increased constructional effort. To adjust thevertical position of the forging punches, there must also be providedspecial adjustment housings for mounting the eccentric shafts, wherebythe machine frame is weakened in its rigidity because of the requiredbearing lugs, and due to the displacement of the center of the eccentricshafts during the adjustment a suitable eccentric shaft drivecompensating this offset is required. When the forging punches arecomposed of two parts screw-connected with each other for adjusting thevertical position, of which screw-connected parts the one isnon-rotatably guided with respect to the forging box and the other isrotatably guided, and the rotatable part communicates with a rotarydrive, so that because of the mutual screw connection of the parts arotation of the rotatable part effects a change in length of the forgingpunch and thus an adjustment of the vertical position, the impairment ofthe load-bearing capacity of the punches must be taken into account inaddition to the lifting movement of the punches, which requires arelative axial movability of the rotating part with respect to therotary drive and likewise leads to a more complex construction.

SUMMARY OF THE INVENTION

It is therefore the object underlying the invention to create a forgingmachine as described above, which is characterized by its novel driveconcept and the related high rigidity and simplified construction.

This object is solved by the invention in that the lifting drives arecomprised of a wobble-plate drive including a wobble plate rotatably anddrivably, but immovably mounted in the forging box about a wobble axisoffset in parallel with respect to the respective forging punch axis anda pressure plate associated to the wobble plate and supported in themanner of a ball-and-socket joint on the end face of the associatedforging punch facing the wobble plate, where preferably the forgingpunches can be pressurized via pressure springs in the sense of africtional connection of wobble plates and pressure plates. By rotatingthe wobble plate, which is eccentric with respect to the forging punchaxis, a lifting movement with a frequency corresponding to therotational speed of the wobble plate is forced onto the forging punch independence on the inclination of the wobble plate and the eccentricity,which lifting movement serves the forming of the workpiece. Theoccurring forging forces are substantially directly transferred from theforging punch via the pressure plate to the wobble plate, which leads topure pressure loads and involves an increased machine rigidity withsimplified supporting conditions. There is a frictional cooperationbetween wobble plates and pressure plates, which is ensured byappropriate loads of the forging punches. There are expediently usedpressure springs, for instance hydraulic cylinders connected to anaccumulator, which urge the pressure plates and wobble plates againsteach other and prevent the same from being lifted off each other.

In accordance with a particularly advantageous aspect of the invention,a shaft stub of the wobble plate is rotatably, but axially immovablyseated in a bearing sleeve axially movably supported in the machine box,so that a change in the vertical position is effected by a longitudinaladjustment of the bearing sleeve independent of the actual liftingmovement of the forging punches, as by means of the change in the axialposition of the wobble plates there are also adjusted the axialpositions of the pressure plates and thus of the forging punches. Thebearing sleeve in addition provides for a stable support of the drumplate, where here as well bending loads are largely avoided.

The bearing sleeve as such might axially adjustably be inserted in themachine box in any suitable way, where a screw drive is, however,particularly suited for longitudinal adjustment, and the external threadof the bearing sleeve engages in an adjusting nut rotatably, but axiallyimmovably supported in the forging box, to which adjusting nut a rotarydrive is associated. Rotating the adjusting nut effects a correspondingchange in the axial position of the bearing sleeve due to its screwconnection with the bearing sleeve, where the parts of the screw drivecan take high loads and transfer the same to the forging box.

When the rotary drives each include a drive gear, which drive gearscooperate with a central wheel mounted at the forging box so as to berotated about the axis of movement, a common adjustment of the verticalposition of all forging punches can be achieved without majordifficulties.

The wobble plate can be driven in various ways, and the wobble plate canfor instance be driven via a toothed-belt drive and together with aperipheral gear rim forms the one crown gear thereof, which wobble platedrive can be accommodated in the forging box in a space-saving way andprovides for the simple use of corresponding transmission ratios toachieve the desired rotational speed of the wobble plate.

To provide a common drive for all wobble plate drives, the wobble platesof all wobble plate drives can be driven via a common bevel geartransmission comprising a large bevel gear mounted on the forging box soas to be rotated and driven about the axis of movement and small bevelgears associated to the wobble plates, which leads to synchronoushammering movements in an economic way. The wobble plate drive aslifting drive is suited not only for forging machines with stationaryforging box, but also for forging machines used as swaging machines, inwhich case the forging box is mounted in a machine frame so as to berotated and driven about the axis of movement. Since the lifting drivesand the vertical position adjusting means are disposed and supported atthe forging box, their mode of function is not changed by the rotarysupport of the forging box, and the common adjustment of the verticalposition and/or the common wobble plate drive are also maintained whenthe respective drive gears are part of planetary gear systems.

BRIEF DESCRIPTION OF THE DRAWING

In the drawing, the subject-matter of the invention is illustratedpurely schematically, wherein:

FIGS. 1 and 2 show an inventive forging machine in a cross-section alongline I—I of FIG. 2 and in an axial section along line II—II of FIG. 1 ona larger scale, and

FIG. 3 shows another embodiment of an inventive forging machine in asectional representation comparable to FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In a forging box 1, forging punches 3 acting against each other arelongitudinally guided in radial recesses 2, which at their radiallyinner ends accommodate forging tools 4. As lifting drive for the forgingpunches 3 wobble plate drives 5 are provided, which are each comprisedof a wobble plate 6 mounted in the forging box 3 so as to be rotated anddriven about a wobble axis T offset in parallel to the respectiveforging punch axis S and a pressure plate 9 associated to the wobbleplate 6 and supported in the manner of a ball-and-socket joint on theend face of the associated forging punch 3 facing the wobble plate via aspherical bearing body 7 and a spherical bearing shell 8. Wobble plate 6and pressure plate 9 are frictionally connected with each other by theirslide faces 10 resting against each other, where the forging punches 3can be pressurized radially outwardly via pressure springs 11 supportedin the machine box 1, thereby urging pressure plates 9 and wobble plates6 against each other. With a shaft stub 12, the wobble plates 6 arerotatably, but axially immovably seated in a bearing sleeve 13 supportedin the machine box I so as to be axially adjustable, where an externalthread 14 of said bearing sleeve in turn engages in an adjusting nut 15which is rotatably, but axially immovably supported in the forging box1, where the adjusting nut 15 can be rotated via a rotary drive 16,which is comprised of a worm 17 and a worm gear rim 18 formed by theadjusting nut 15 on the outer periphery. The worm 17 is connected with adrive gear 19, which drive gears 19 are meshing via intermediate wheelswith a central wheel 21 mounted at the forging box 1 so as to be rotatedand driven about the forging axis A. Therefore, when the central wheel21 is driven, a rotary adjustment of the adjusting nut 13 and thus achange in the axial position of the bearing sleeve 13 is effected viathe rotary drive 16, whereby the wobble plate 6 is adjusted axially, andthe vertical position of the forging punches 3 is also changednecessarily.

For driving the wobble plate 6 a toothed-belt drive 22 is used, whoserotating toothed belt 23 connects a peripheral gear rim 24 of the wobbleplate 6 as crown gear with a crown gear 26 seated on a parallel bevelgear shaft 25. On the bevel gear shaft 25 a small bevel gear 27 isseated, which is meshing with a large bevel gear 28 mounted on theforging box 1 so as to be rotated and driven coaxial to the forging axisA. Driving this large bevel gear 28, for instance via a pulley 29,therefore leads to driving the toothed-belt drive 22 and thus to therotation of the wobble plate and the lifting movement of the forgingpunches 3.

The embodiment illustrated in FIG. 3 shows a similar forging machine 1,where identical parts are also provided with identical referencenumerals, with the exception that with this machine the forging box 3 isrotatably and drivably mounted in a machine frame 30 and can be rotatedabout the forging axis A via a drive indicated only with a drive gear31, so that the forging machine can be used as swaging machine. Sincethe wobble plate drives 5 as well as the vertical position adjustingmeans together with their drives are arranged and supported on themachine box, the functions of lifting drives and vertical positionadjusting means remain unchanged and can be used without any problemeven while the forging box rotates at the same time.

What is claimed is:
 1. A forging machine comprising (a) a forging box,(b) at least two forging punches guided in a longitudinal directionalong a forging punch axis in the forging box and acting against eachother, (c) a separate wobble-plate drive for displacing each one of theforging punches in the longitudinal direction, each wobble-plate drivecomprising (1) a wobble plate rotatably drivable about a wobble axis,the wobble axis extending parallel to, but offset from, the forgingpunch axis, and the wobble plate being immovable along the wobble axis,and (2) a pressure plate engaging the wobble plate and supported on anend face of the forging punch, the pressure plate forming aball-and-socket joint with the end face, and (d) pressure spring meansbiasing the forging punch in the longitudinal direction to press thepressure plate and the wobble plate into frictional engagement.
 2. Theforging machine of claim 1, wherein the wobble plate has a stub shaft,the stub shaft being rotatably, but axially immovably, mounted in abearing sleeve, the bearing sleeve being axially adjustably mounted inthe forging box.
 3. The forging machine of claim 2, wherein the bearingsleeve has an external thread meshing with an adjusting nut, theadjusting nut being rotatably, but axially immovably, supported in theforging box, and further comprising a rotary drive connected to theadjusting nut.
 4. The forging machine of claim 3, wherein the rotarydrive comprises a drive gear and a central wheel mounted on the forgingbox, the drive gear meshing with the central wheel and the central wheelbeing rotatable about a forging axis extending perpendicularly to thelongitudinal direction.
 5. The forging machine of claim 1, furthercomprising a toothed-belt drive for rotatably driving the wobble plate,the wobble plate having a peripheral gear forming one of the gears ofthe toothed-belt drive.
 6. The forging machine of claim 1, furthercomprising a common bevel gear transmission for rotatably driving allthe wobble plates, the transmission including a large bevel gear mountedon the forging box for rotation about a forging axis extendingperpendicularly to the longitudinal direction and a small bevel gearassociated with each wobble plate and meshing with the large bevel gear.7. The forging machine of claim 1, further comprising a machine frame,the forging box being mounted in the machine frame for rotation about aforging axis extending perpendicularly to the longitudinal direction.